It's a crap shoot. People will drop the same phone from the same height and one will break where the other doesn't. It's all about how it lands.
I will say that I think the Lumia 920, like the iPhone is a bit more susceptible to breakage because the glass goes so close to the edge. Also, based on how I broke my first Lumia 920, I'd say that the phone is more susceptible to flexing. One corner of the screen broke, but then I also had a crack right across the middle of the screen.
Gorilla glass is noted for scratch resistance, not withstanding impacts. The force experienced in a drop is far beyond the strength of the glass, even if it's better than conventional glass.
My first phone fell screen first and slid a few feet on asphalt and got no scratches. My current Lumia 920, despite care in handling and empty pockets, managed to acquire a 2mm scratch towards the edge of the screen. I had my previous phone for nearly 2 years before it picked up a scratch. Go figure.